Red Brown vs Mustard Brown

How close are they?

ΔE 10.7, fair: the same colour family, but not a straight swap. Mustard Brown is a little lighter, more saturated than Red Brown.

Can I use Mustard Brown instead of Red Brown?

Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Mustard Brown is a little lighter, more saturated than Red Brown.

Can I use Red Brown instead of Mustard Brown?

The same difference applies the other way round: Red Brown is a little darker, more muted.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.